build: fix parameter name in cmake

Fix the parameter name in `_add_swift_library_single` which would
previously not pass any value for the `INSTALL_IN_COMPONENT` due to a
missed alteration when the function was refactored.  Spotted by
inspection.

Author: compnerd

cmake/modules/AddSwift.cmake

@@ -866,7 +866,7 @@ function(_add_swift_library_single target name)
       ${SWIFTLIB_SINGLE_IS_STDLIB_CORE_keyword}
       ${SWIFTLIB_SINGLE_IS_SDK_OVERLAY_keyword}
       ${embed_bitcode_arg}
-      INSTALL_IN_COMPONENT "${SWIFTLIB_INSTALL_IN_COMPONENT}")
+      INSTALL_IN_COMPONENT "${SWIFTLIB_SINGLE_INSTALL_IN_COMPONENT}")
   add_swift_source_group("${SWIFTLIB_SINGLE_EXTERNAL_SOURCES}")
 
   # If there were any swift sources, then a .swiftmodule may have been created.